Hover

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With no annotations, the description carries the full burden. It does usefully disclose that the pointer is left on the element (a persistent state change) and that the response reflects what appeared, but it says nothing about failure modes for missing elements, whether prior hover state is cleared, or whether the element is scrolled into view first.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

One sentence, front-loaded with the action and followed by the observable result after a semicolon. Every clause earns its place with no filler.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a single-parameter interaction tool with no output schema, the definition covers the action, the residual pointer state, and the shape of the return well enough to call it correctly. The remaining gap is error and pre-condition behavior, which matters more here because no annotations exist to cover it.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Only one parameter, and the schema documents it fully ('An element id from a listing, such as a12') at 100% coverage. The description's 'the element' adds no meaning beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description gives a concrete verb and target: 'moves the pointer onto the element and leaves it there', which is clearly distinct from the sibling 'click'. The parenthetical return hint ('a menu, a tooltip') further pins down what hover produces, though it never explicitly contrasts itself with click or tap.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is only implied: an agent can infer it should call this when it needs hover-revealed content such as menus or tooltips. There is no explicit when-to-use versus when-not guidance, and no mention of prerequisites like the element being visible or in the viewport.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.